FF8 by Hoya

Preferred Very Common Environmentally Dangerous

FF8 by Hoya is a preferred optical glass with a very common melt frequency. It transmits from 0.36 to 1.55 µm with an nd of 1.75211 and a Vd of 25.05. It has low thermal expansion (CTE of 6.1×10⁻⁶/K), excellent chemical resistance, and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.36501–1.5296 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.36501–1.5296 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.360–1.550 µm
Optical Properties
Refractive Index (nd) 1.75211
Abbe Number (Vd) 25.05
Dispersion Formula Schott
Wavelength Range 0.36501 — 1.5296 µm
$$n(\lambda) = \sqrt{2.95644 - 0.0197622\,\lambda^2 + 0.0298788\,\lambda^{-2} + 0.00518309\,\lambda^{-4} - 0.000542024\,\lambda^{-6} + 4.84632 \times 10^{-5}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 6.1
TCE 100/300°C (10-6/K) 7.0
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-3.67 \times 10^{-6} + 2(1.1 \times 10^{-8})\,\Delta T + 3(-3.23 \times 10^{-11})\,\Delta T^2 + \frac{7.57 \times 10^{-7} + 2(9.89 \times 10^{-10})\,\Delta T}{\lambda - 0.306}\right] \Delta T = T - T_0, \quad T_0 = 23\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.14
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance 1
Acid Resistance 1
Alkali Resistance —
Phosphate Resistance —
Notes

Recommended glass type

Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
TPH55 Ohara 1.755502 25.066156
SF14 Sumita 1.76182 26.5
K-SFLD14 Sumita 1.76182 26.5
S-TIH14 Ohara 1.761821 26.517885
TIH14 Ohara 1.761821 26.517966
N-SF14 Schott 1.76182 26.53
SF14 Schott 1.76182 26.53
PBH14 Ohara 1.761819 26.553651
PBH14W Ohara 1.761819 26.553651
ZF12 CDGM 1.761822 26.555686
Similar Glasses (Hoya)
Glass Manufacturer nd Vd Compare
FD14 Hoya 1.761823 26.552048
FD140 Hoya 1.76182 26.61
FDS5 Hoya 1.761804 26.914901
E-FD4L Hoya 1.7552 27.53
E-FD4 Hoya 1.7552 27.53
FD4 Hoya 1.755199 27.530242
FD41 Hoya 1.750839 27.686615
E-FD13 Hoya 1.74077 27.76
FD13 Hoya 1.740774 27.764991
FD3 Hoya 1.739999 28.245048
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